Research Institute for Sustainable Urban Development: a Brief Overview

Transcription

1 Research Institute for Sustainable Urban Development: a Brief Overview Jin-Guang Teng 滕锦光 Director of Research Institute for Sustainable Urban Development (RISUD), Ko Jan Ming Professor of Sustainable Structures and Materials & Chair Professor of Structural Engineering network.nationalpost.com 6 January

2 Opportunities for Hong Kong Hong Kong is a unique model of high-density cities characterized by high-rise residential blocks Most large cities in the mainland are becoming like Hong Kong Hong Kong is ahead of the Chinese mainland in urbanization by at least two decades Hong Kong s dense urban environment is a living laboratory for R & D World-class research at PolyU in related areas Examples of Hong Kong s areas of opportunity: Public transport systems GPS navigation of vehicles Management of underground assets network.nationalpost.com 2

3 Vision: To be a world leader in the development and dissemination of innovative solutions for sustainable high-density urban development RISUD was officially inaugurated in June 2013 Mission: To create innovative solutions to problems generated by high-density urban development through multidisciplinary, collaborative research; To engage in knowledge transfer activities by collaborating with industry and government; and To make an impact on societal cultures of urban sustainability through community engagement and services.

4 Organizational Chart International Advisory Committee Management Committee Director and Associate Directors Executive Committee Division of Urban Systems Division of Urban Infrastructure Division of Urban Environment Division of Green Buildings Division of Smart Cities Research Group 1 Research Group 2 Research Group 3 Research Group 25 Research Group 26 Researh Group 34 Innovative Solutions for Sustainable Cities 4

5 Key Characteristics of RISUD Aimed at high-impact solutions for pressing socio-economic problems Integration of expertise for multi-disciplinary and/or collaborative research Incentive funding from RISUD to encourage multi-disciplinary/collaborative research Collaboration with government and industry for real-world impact 5

6 University-Government-Industry (UGI) Consortium for Sustainable Urban Development (Initiated and currently hosted by RISUD) Government Departments Architectural Services Department Buildings Department Civil Engineering and Development Department Drainage Services Department Electrical and Mechanical Services Department Environmental Protection Department GLTS Section of the Development Bureau Highways Department Hong Kong Observatory Housing Department Planning Department Transport Department Water Supplies Department Universities (8 members) CityU CUHK HKBU (2 centres) HKU HKUST (2 centres) PolyU Industry (26 members) AECOM Asia CLP Power Gammon Construction Hongkong Electric MTR Corporation Ove Arup & Partners Siemens Limited Sun Hung Kai Properties

7 Strategic Focus Areas (Selected/under consideration) Smart and grid-responsive buildings (selected) Urban water management (selected) Urban simulation (tentatively selected) Air quality and urban health Innovative land supply Robotics in construction Industrialization of construction Sustainable urban infrastructure

8 Sustainable Marine Infrastructure: Challenges and a Promising Solution Jin-Guang TENG Ko Jan Ming Professor in Sustainable Structures and Materials, Chair Professor of Structural Engineering & Director of Research Institute for Sustainable Urban Development (RISUD) The Hong Kong Polytechnic University

9 Needs for Marine infrastructure Hong Kong-Zhuhai-Macau Bridge Hong Kong Airport Third Runway Artificial islands Land reclamation in Hong Kong / Wind energy farm Marine Infrastructure Projects Floating island Belt and Road Initiative Offshore drilling platform

10 Very Large Floating Structures Floating wind farms Floating solar farms Floating airports Floating islands/cities

11 Offshore wind energy The world s first full-scale floating wind turbine, Hywind en.wikipedia.org 11

12 Offshore solar energy The Kyocera Corporation s Kagoshima Nanatsujima Mega Solar Power Plant can generatie enough electricity to power roughly 22,000 homes. 12

13 Marine environment Steel-reinforced concrete (RC) structures Steel Concrete Steel corrosion Constituent materials of concrete Cement Water Sand Gravel

14 Challenge posed by steel corrosion High maintenance costs of steel-rc structures Steel corrosion costs about 3% of GDP ( United States (ASCE 2013): The US would need to invest US$3,600 billion over eight years to maintain a state of good repair for its infrastructure The challenge for Hong Kong and the Chinese mainland is similar (Jin et al. 2007): About 24% of bridges in costal regions suffered from steel bar corrosion and corrosion-induced cracking. Lowe s Motor Speedway Bridge collapse Cochin Bridge collapse I-35W Mississippi River Bridge collapse

15 What is FRP? Fibres FRP products for new construction Polymer Fibre-reinforced polymer (FRP) composites are formed by embedding continuous fibres in a polymeric resin matrix In North America, many bridges have been built with FRP reinforcing bars (rebars) FRP products for use in civil engineering Types of FRPs: glass FRP (GFRP), carbon FRP (CFRP), aramid FRP (AFRP), and basalt FRP (BFRP), etc. GFRP made of glass fibers and vinyl ester resin (Courtesy is ourof main Prof Mufti) focus FRP profile FRP bridge deck FRP stirrups FRP rebars FRP tube

16 Strength retention Durability of FRP Composites Durability of GFRP bars in marine environments Xian (2016) Almusallamn et al. (2012) Exposure duration (days)

17 Durability of FRP Composites Durability of GFRP bars in marine environments GFRP bars embedded in mortar Complete immersion in salt solution (3% NaCl-Sodium Chloride) Accelerated aging at 20, 40, 50 and 70oC (Tg) Different durations (60, 120, 210, 365 days) Courtesy of Prof. Brahim Benmokrane, University of Sherbrooke, Canada

18 Durability of FRP Composites Durability of GFRP bars in marine environments Courtesy of Prof. Brahim Benmokrane, University of Sherbrooke, Canada

19 International Workshop on Seawater Sea-sand Concrete (SSC) Structures Reinforced with FRP Composites, 13 December 2016, Hong Kong Polytechnic University Long-Term Exposure Performance of FRP Composites in Marine Environments Itaru Nishizaki, Iwao Sasaki & Hiroki Sakuraba Public Works Research Institute, Japan Innovative Materials & Resources Research Center (imarrc) (Extracted slides with some adaptations by JG Teng)

20 Exposure location used in this test Facilities for exposure tests: 8.9 meters from the tidal level Second deck 8.9m Exposure station Climate: Typical mainland Japan Annual mean temp.: 16.6 ; Annual rainfall: 2016 mm/y; Global solar radiation 14.7MJ/m 2. Corrosivity based on ISO9223: C-4 (High) (3 rd deck) (Courtesy of Dr Itaru Nishizaki, Public Works Research Institute, Japan)

21 Sample name FRP cables/rods CFRP1 CFRP2 used in AFRP1 the tests AFRP2 GFRP VFRP Shape Strand Rod Rod Braided Rod Rod Fiber type Carbon Carbon Aramid Aramid E-glass Vinylon Matrix resin Epoxy Epoxy Vinyl ester Epoxy Vinyl ester Epoxy Vf (%) Diameter (mm) Ultimate load (kn) Modulus (GPa) Anchor system Adhesive Wedge Adhesive Adhesive Adhesive Adhesive Note: The GFRP & VFRP bars used in the testing programme were not developed for the reinforcement of concrete members (Courtesy of Dr Itaru Nishizaki, Public Works Research Institute, Japan)

22 Specimens exposed to open marine environment: water, salt, sunlight, thermal cycles etc. Exposure Condition With/without direct sunlight Specimens with tension (in a stainless steel flame, 1m) Two initial load levels were adopted for each FRP type Without direct sunlight With direct sunlight Specimens without tension (Courtesy of Dr Itaru Nishizaki, Public Works Research Institute, Japan)

23 Residual tensile load (%) Residual tensile load (%) Results of residual tensile resistance 3.5years in tension years in tension % 80% 60% 40% 20% 0% 100% 80% 60% 40% 20% 0% With direct sunlight 0 0,2 0,4 0,6 0,8 1 Initial tensile load ( Pu) GFRP With direct sunlight GFRP CFRP & AFRP VFRP CFRP & AFRP VFRP 0 0,2 0,4 0,6 0,8 1 Initial tensile load ( Pu) Influence of the initial load level Residual tensile resistance CFRP/AFRP: 70-80% retained after 17 years (at Pu) * GFRP: 80% retained (at 0.25Pu) after 17 years; Creep ruptured at 0.4Pu after 17 years ( * For AFRP2, at Pu) (Courtesy of Dr Itaru Nishizaki, Public Works Research Institute, Japan)

24 Effect of direct sunlight on residual tensile resistance Residual tensile load (%) Residual tensile load (%) Residual tensile load (%) Residual tensile load (%) 100% 100% 3.5years in tension % 60% 40% 20% 0% With direct sunlight 0 0,2 0,4 0,6 0,8 1 80% 60% 40% 20% 0% Without direct Sunlight 0 0,2 0,4 0,6 0,8 1 CFRP1 CFRP2 AFRP1 AFRP2 GFRP Initial tensile load ( Pu) Initial tensile load ( Pu) 100% Slight but clear influence of sunlight was observed 100% 17years in tension % 60% 40% 20% 0% With direct sunlight 0 0,2 0,4 0,6 0,8 1 80% 60% 40% 20% 0% Without direct Sunlight 0 0,2 0,4 0,6 0,8 1 CFRP1 CFRP2 AFRP1 AFRP2 GFRP Initial tensile load ( Pu) Initial tensile load ( Pu) With direct sunlight Without direct sunlight (Courtesy of Dr Itaru Nishizaki, Public Works Research Institute, Japan)

25 Tensile rupture load (kn) Results of residual tensile resistance: CFRP Pre-stressed specimens, outdoor open exposure Overall findings: almost no major change CFRP1 under direct sunlight and a high prestress ratio: slight reductions 150 after 3.5years exposure after 17years exposure Max. Min. in variation Initial average strength Min. in variation after 17years 0 exposure Initial load ( Pu) ial Direct sunlight With Without With Without rec CFRP1 CFRP2 (Courtesy of Dr Itaru Nishizaki, Public Works Research Institute, Japan)

26 Sea-sand seawater concrete (SSC) + FRP Sea-sand and seawater FRP products If steel is no longer used as the reinforcing material, then sea-sand and seawater can be used to make concrete Steel River sand Fresh water FRP Sea sand Seawater

27 Sustainability benefits: I We can save fresh water, river sand, and energy Protect the environment; Reduce carbon emissions Damage to rivers and mountains by sand and gravel mining

28 Sustainability benefits: II Cement production consumes great amounts of energy and accounts for about 5% of global CO 2 emissions Relaxing chloride limits for cement allows the use of waste materials as fuels in cement production Combining wastes incineration with energy recovery!

29 Cost (HK$) Cost (HK$) Life-cycle cost analysis The life-cycle cost of FRP-SSC is only half that of steel-rc for a large structural member with a service life of 100 years Life-cycle cost (steel-rc) Life-cycle cost (FRP-SSC) Total life-cycle saving Steel-RC FRP-SSC Initial cost (FRP-SSC) Initial cost (steel-rc) Life-cycle advantage at the first major maintenance action Service time (years) 0 Initial cost Life-cycle cost

30 International Workshop on Seawater Sea-sand Concrete (SSC) Structures Reinforced with FRP Composites, 13 December 2016, Hong Kong Polytechnic University

31 Grand challenge How well will the new type of structures perform in 50 years, 100 years or even longer? Accelerated aging tests Artificial environmental chamber Field exposure tests Key issues: (i) Simulation of a subtropical climate like that in Hong Kong and nearby regions (ii)combined mechanical and environmental actions. Accelerated laboratory tests FRP-SSC beam Atmospheric zone Beam-to-column connection FRP-SSC column Sea water FRP-SSC column FRP-SSC slab Different marine climates Splash zone Tidal zone Submerging zone Field performance

32 Concerns with accelerated durability tests Traditional ways of accelerated laboratory durability tests Increase temperature Increase concentration Cl - Cl - Cl - Cl - Lower concentration Cl - Cl- Cl - Higher concentration Simplistic empirical extrapolation must be avoided as the deterioration mechanism may change! When did boiling an egg ever produce a chicken? by Kinloch (1997)

33 Grand scientific challenge From molecular dynamics to structural behaviour: A multi-scale multi-physics approach for predicting life-cycle performance Accelerated Laboratory Tests Short-Term Theoretical Models for FRP- SSC structures from experiments and analysis INPUT COMPARE Predictive Method COMPARE INPUT Time-Dependent Constitutive Models from multi-scale multi-physics modelling + experiments Field exposure Tests

34 Research programme Task 1: Fundamental mechanisms of SSC Material chemistry and science Leader: Zongjin Li Task 2: Innovative forms for FRP-SSC structures Structural behaviour and analysis Leader: Jin-Guang Teng Task 4: Material deterioration and constitutive modelling Material deterioration science Leader: C. K.Y. Leung FRP-SSC structures Task 5: Structural deterioration and modelling Structural behaviour and analysis Leader: Jin-Guang Teng Task 3: Performance evolution monitoring methodology Structural health monitoring Leader: Yi-Qing Ni

35 Thank you for your attention! Questions?